Radar wave simulation using three-dimensional multi-region pseudospectral time domain algorithm with directional Kirchhoff integration surface

We present a three-dimensional (3D), multi-region (MR) pseudospectral time domain (PSTD) method with directional Kirchhoff integration (DKI) surface for simulating electromagnetic (EM) wave propagation in large domain heterogeneous media. The basic idea is to divide the whole computational domain into a number of sub-regions containing strong scatters embedded into a uniform background. The PSTD method is used to compute the EM field inside all the sub-regions, while Kirchhoff integration techniques are used to compute the EM field in the uniform background. As the result a 3D multi-region PSTD method with directional Kirchhoff integration surface concept (DKI/MR/PSTD) is presented. An application in through-wall detection is introduced in the source sub-region with heterogeneous scatters. Comparison of the results obtained in this approach with single-region PSTD demonstrates the validity of DKI/MR/PSTD in simulation of through-wall detection cases. Later time multiple refraction and reflection of EM wave trains can be clearly simulated besides the first wave phase in the heterogeneous source sub-region. The EM waveforms simulated from DKI/MR/PSTD coincide well with those corresponding phases from the classical single-region PSTD. Moreover, the signal to noise ratio in EM waveforms simulated by DKI/MR/PSTD is higher than those obtained by single-region PSTD. For the given test case the computation time of DKI/MR/PSTD is less than 1/3 of that used by the classical single-region PSTD. The memory requirement by DKI/MR/PSTD is about one half of the classical PSTD. The results show that the DKI/MR/PSTD method is valid for EM wave propagation simulation.